MONDAY, Oct. 1 (HealthDay News) -- Despite government agency reports suggesting a decrease in child abuse cases, new data show that the number of children hospitalized due to serious abuse-related injuries actually increased slightly from 1997 to 2009.

In the new study, researchers analyzed U.S. hospital statistics from the Kids Inpatient Database. During this 12-year period, the incidence of serious injuries due to child abuse -- including fractures and abusive head trauma -- increased by 4.9 percent. By contrast, child protective service records showed a 55 percent decrease in child abuse injuries in that time period.

The new findings appear online Oct. 1 and in the November print issue of Pediatrics.

Many reasons could account for the apparent disconnect, said study co-author Dr. John Mishel Leventhal, a professor of pediatrics at the Yale School of Medicine.

For starters, "we were looking at the most serious injuries that require hospital stays, while others have looked at child abuse rates overall," he said. There may also have been changes in reporting and injury coding as well as the criteria for who is admitted to the hospital.

The new data show that serious abuse-related hospitalizations are more common in infants under 1 year old and tend to disproportionately affect families on Medicaid, the U.S. health program for low-income individuals and families. "Rates of stress may be high in poorer families, and stress is linked to risk of abuse," Leventhal said.

"Prevention messages must be clearer, louder and heard in various settings including health care, daycare, parent support groups," he said. To really make a dent in the rates of serious abusive injuries in children, a national awareness and prevention campaign is needed, the researchers suggested.

Many children are injured by people who are not related to them, Leventhal warned. "Be careful about whom you leave your kids with, and even if it is embarrassing, say 'Don't hurt my kid when you take care of them.'" He said he often advises parents to "take five" when they feel frustrated: "Step back, take a deep breath and walk out of the room."

The findings point to the challenges of using any one source of data to track child abuse, said Dr. Andrew Adesman, chief of developmental and behavioral pediatrics at Steven and Alexandra Cohen Children's Medical Center of New York, in New Hyde Park.

"These are all preventable injuries, and the canary in the coal mine," Adesman said. "Abuse is a signal that there are problems in the household or parenting that can't be ignored. We need to do better in terms of prevention and earlier intervention in these homes."